Submission #307579

#	Time	Username	Problem	Language	Result	Execution time	Memory
307579		Mounir	Rack (eJOI19_rack)	C++14	100 / 100	14 ms	8192 KiB

rack

#include <bits/stdc++.h>
#define int long long
#define chmin(x, v) x = min(x, v)
#define chmax(x, v) x = max(x, v)
#define all(v) v.begin(), v.end()
using namespace std;

const int MOD = 1e9 + 7, N = 1e6 + 5;
int puissance[N];

signed main(){
	puissance[0] = 1;
	for (int expo = 1; expo < N; ++expo) puissance[expo] = (puissance[expo - 1] * 2)%MOD;
	
	int nBits, val, sum = 1;
	cin >> nBits >> val;
	val--;
	
	for (int iBit = 0; iBit < nBits; ++iBit){
		if (val%2 == 1) sum = (sum + puissance[nBits - 1 - iBit])%MOD;
		val /= 2;
	}
	cout << (sum + MOD)%MOD<< endl;
	return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 60 / 60